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Desert Diary


Much of the information necessary to understand the natural world comes from collections of organisms. Only by collecting can many of the vital statistics of organisms be obtained and documented. Distribution, genetic relationships, population structure, population and ecological health, changes through time—all these and more require the collection of samples. This unhappy fact disturbs many people, including the scientists themselves. The researchers, however, know something that few of the general public understand—that many more offspring are conceived than can survive.

For most species, then, careful collecting doesn't harm the population—removing organisms opens up resources for individuals that otherwise were doomed. Thus in areas around universities where samples have been collected for scores of years, populations remain hale and healthy except where impacted by pollution or other environmental degradation.

It was the realization that part of each generation dies before reproduction that gave Darwin the clue as to how evolution produces adaptation. Those better fit for their environment survive more often than those who don't, birthing a more fit next generation—Darwin's "descent with change".
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Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.

Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.